Method of assisting combustion in furnaces



Feb. 12, 1929. 1,701,855

G. P. JACKSON METHOD OF ASSISTING COMBUSTION IN FURNACES Original Filed March 29, 1922 2 sheet -Sheet, 2

INVENTOR. gas/W 5 Film/ sow A TTORNEYS.

Patented Feb. 12, 1929.

UNITED STATES.

PATENT OFFICE.

GEORGE r. JACKSON, or FLUSHING, NEw roan, ASSIGNOR 'ro IN'rEnNArIoNAL co l:-

BUS'I'ION ENGINEERING CORPORATION, on NEW YORK, N. Y., a CORPORATION or DELAWARE.

I METHOD OF ASSISTING C OMBUSTION IN FURNACES.

Original application filed March 29, 1922, Serial No. 547,679. Divided. and this application filed June 6,

a 1925, Serial No. 35,298.

The present invention has special reference to a method of assisting combustion in a furnace, and reducing liability of clinkers and other injurious deposits forming on the wall of the fire-box of a furnace.

An object of the invention is to provide a novel and improved method 'of this char-- acter which is particularly adapted for use in a pulverized fuel furnace.

The several features of the invention whereby the above mentioned and other objects of the inventionmay be attained will be clearly understood from the following de-.

scription and accompanying drawings, in which-- Fig. 1 is a longitudinal vertical sectional view, partly in elevation, of a portion of a pulverized fuel furnace which is particularly adapted for use in carrying out my improved method;

Fig. 2 is a transverse vertical sectional view taken on the line 22 of Fig. 1, certain parts which would appear in elevation being omitted;

Fig. 3 is a vertical sectional view, on an enlarged scale and partly broken away, of a portion of a side wall of the fire-box of the furnace;

Fig. 4 is a front view of the portion of the side wall illustrated in Fig. 3; and

Fig. 5 is a sectional plan view taken on the line 5-5 of Fig. 3.

The pulverized fuel furnace illustrated in the drawings may be and preferably is the same as the one described and claimed in my pending application Ser. No. 547,679 filed March 29, 1922, of which the present application is a division. As shown this furnace is provided with a steam boiler 2, [and a fire-box 4 having side walls 6, front wall 7, rear or bridge-wall 8, a top wall 10, and a bottom wall 11. A pulverized fuel nozzle 12, suitably connected with a source of fuel supply is mounted in the top wall and is so arranged as to direct the pulverized fuel downwardly into the firebox. In this type of furnace the combustion of the fuel takes place while the fuel is in suspension and the furnace draft tends to direct the suspended mass of burning fuel and the gases upwardly to the boiler as indicated by arrows in Fig. 1 of the drawings.

As illustrated the inner sides of the four vertioal walls of thefire-box are each profour walls opening one into the other to form I a series of three recesses completely encompassing the interior of the fire-box. The recesses 14 are provided with horizontal upper and lower walls 16 and the recesses in the front and side Walls of the fire-box are provided with an inner vertical wall 18. The recesses in the bridge wall 8 of the fire-box lead from an air chamber 20 formed in the bridge wall, which is connected at its lower end with a suitable source of air supply through a pipe 22. The portions of the walls of the fire-box between the recesses 14, the portion of the walls immediately below the lower recesses 14 and the portions of the walls above the upper recesses 14 are provided with downwardly and inwardly inclined surfaces 24. A series of blocks-26 of refractory material are arranged end to end in the recesses 14 so as to form three rows of blocks completely encompassing the interior of the'firebox. The blocks 26 in the front and side walls of the fire-box are spaced from the vertical walls of the recesses 14 so as to provide air passages 28 leading from the air chamber 20, and the blocks in the bridge wall 8 extend through the recesses, so that the three rows of blocks are completely surrounded by air spaces in communication. with a source of air supply. The blocks 26 project a distance beyond the upper edges of the inclined surface 24 of the fire-walls, and the inner surfaces of the blocks are inclined similarly to the inclined surfaces 24 and form continuations thereof.

Each block 26 is provided with two downwardly'directed air ducts 30 that are in communication with the {air passages 28 throu h two channels 32 in the top of the block. T e walls 34 of the air ducts 30 are inclined the same as the inclined surfaces 24 of the firewall, and are so arranged as to form continuations of these surfaces. The other walls 36 of the air ducts 32 are at a less angle to the vertical than the walls 34 and these Walls are so spaced as to provide a relatively wide and shallow passage between them that tapers downwardly.

-With this construction it will be apparent 'that upon the admission of air to the air the heavier particles of burning fuel. in suspension that would otherwise drop to the bottom of the furnace only partially burned.

The downwardly directed air for combus tion in connection with the downwardly moving portion of the fuel and flame stream, is advantageous as there is less violent eddying of the descending stream than would be the case were the air admitted through the front wall or side wall in a direction transverse that of the descending fuel. Furthermore, where there are a plurality of burners there is a tendency of the air when admitted horizontally through the front wall, to short circuit some of the fuel directly to the tubes, particularly in the upper part of the combustion chamber before the individual streams of entering fuel have had the opportunity to unite in one general stream. The downward admission of the air obviates this. In addition, the downward admission of the air causes such air to travel farther along with the fuel stream bordering it on the convex side before commingling takes lace. This tends to insure the body of air or the heavier particles to gravitate into and there find. the oxygen for combustion.

It may also be noted that the downward admission of air adjacent the ascending portion of the fuel is advantageous for the reason that at such place more violent eddying of the fuel and flame stream is required to secure the intimate admixture necessary to complete combustion. In the ascending portion of the'fuel and flame stream there are large bodies of expanded gases and since the volume is so great there is need for more or. less violent eddying to get the proper mixture. In contra-distinction the entering fuel has some of the air required for combustion with it and, therefore, a less measure of eddying is required.

It will also be' apparent that the cooling effect of the air films on the inclined surfaces 24 of the fire wall will tend to prevent the formation of clinkers thereon and to prevent these surfaces from wearing away or spalling. These films of air directed over the inclined surfaces also will tend to prevent cinders or, dust lodging on these surfaces and to direct it inwardly toward the center of the fire-box. In case any drip should be formed by the melting of dust on the projecting portions of the blocks 26, which form a drip ledge, the currents of air from the passages 30 by creating a cool air zone extending to the inner edge of the blocks would cooperate with the inclined inner surfaces of the blocks to cause the drip to solidify into a slag or clinker projecting downwardly and inwardly from the inner edge of the blocks in substantially the plane of the inclined inner surfaces as indicated at 40 in Figure 3, and it will .be apparent that any further drip would solidify on the slag initially formed before it could reach the bottom sides of the projecting portions of the blocks, so that there is no danger of slag forming on these bottom side portions of the blocks and blocking the air passages.

As will be evident to those skilled in the art, my invention permits various modific'ations without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

1. The method of burning fuel in suspension in a combustion chamber having an outlet in anupper part which includes admitting the fuel in an upper part of the chamber in a downward'direction so that the fuel and flame stream reverts on itself in a substantially U-form, in admitting a downwardly directed supporter of combustion between the furnace or chamber structure and the descending portion of the fuel and flame stream and a downwardly directed supporter fuel and flame stream and the four upright walls of the chamber.

3. The method of burning fuel in suspension in a combustion chamber having an out let in an upper part, which includes admitting the fuel in an upper part of the chamber in a downward direction so that the fuel and flame stream reverts on itself in a substantially U-form and in admitting a downwardly directed body of air between the fuel and flame stream andthe four upright walls of the chamber at a plurality of points in the height of the chamber.

4. The method of burning fuel in suspension in a combustion chamber having an outlet in an upper part, which includes admitting the fuel and a portion of the air required for combustion in an .upper part of the chamber in a downward direction so that the fuel and flame stream reverts on itself in a substantially U-form, and admitting further air for combustion at successive points in the height of the furnace, such air being directed downwardly.

.5. The method of burning fuel in suspension in a combustion chamber which includes admitting the fuel in a downwardly directed stream adjacent a wall of the chamber and in a direction generally substantially parallel therewith, and in admitting a combustion supporting medium through such wall in a stream directed generally substantially parallel with the entering stream of fuel and downwardly between said wall and said stream.

6. The method of burning fuel in suspension in a combustion chamber which includes admitting fuel adjacent a wall of the chamber and in a direction generally substantially parallel therewith, and in admitting a combustion supporting medium through such wall in a stream directed generally substantially parallel with the entering stream between said wall and the entering stream of fuel and moving in the same general direction.

7 The method of burning fuel in suspension in a combustion chamber having an outlet in an upper part, which includes admitting the fuel at a point such that the fuel and flame stream in progress through the chamber rises toward the outlet, and in admitting a downwardly directed body of air between the rising ortion of the flame stream and the cham er wall structure.

8. The method of burning fuel in suspension in a combustion chamber having an outlet in an upper part, which includes admitting the fuel at a point such that the fuel and flame stream 1n progress through the chamber rises toward the outlet, and in admitting a downwardly directed body of air between the rising portion of the flame stream and the chamber wall structure at a plurality of points in the height of the fur- 40 nace.

9. The method of burning pulverized fuel in suspension in a combustion chamber in which the fuel moves in a stream between the longitudinal side walls thereof and from the forward portion toward the rear portion of the combustion chamber, which includes admitting air through said side walls in a downward direction and at opposite longitudinal sides of the stream of fuel.

10. The process of fine fuel combustion which comprises feeding downwardly into a combustion chamber a stream of air and fine fuel, and also introducing at a lower level and at one side of the fuel stream a downwardly directed flow of supplemental air under pressure.

11. Method of burning pulverized fuel which consists in introducing into a combustion zone having a draft outlet, fuel and air 69 in a downwardly projected stream, so that the fuel in combustion takes a return bent course to the draft outlet, and introducing air under pressure into the combustion zone as a thin laterally extended stream directed downwardly along substantially the width of one wall of the zone at one slde of the path of the fuel.

In testimony whereof, I have signed my name to this specification this 2nd day of 70 June, 1925.

GEORGE P. JACKSON.

CERTIFICATE OF CORRECTION.

Patent No. 1,701,855.

Granted February 12, 1929, to

GEORGE P. JACKSON.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 8, claim 5, strike out the words "of fuel"; same page. line 17, claim 6, after the word "directed" insert the words "between said wall and the entering stream of fuel", and lines 18 and 19, strike out the words "between said wall and the entering stream"; and that the said Letters Patent should be read with these corrections therein that the-same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of March, A. D. 1929.

(Seal) M. J. Moore, Acting Commissioner of Patents.

GERTIFEQATE GQRREZGTMN.

mam Nan 1,701,855. Gramwd February 12 m EQRGE 9. JALGKSON.

it is hereby ceriified that ermr aggears in he printe specification @f the arav numbered patent requiring cafirectien as :Mfiwws; Fage 3, Rim 8, .caim f5, strike out the words "0'? fuel"; sama paga, Male 37, 65am; fififihi' Hm word mfeaazi" insert the Wmds "bflwean maid Wail am film 0f fuel, 165 lines 18 and E9, strike cm the Words i1etween said Wail and ihe stream"; and that the said Le texs Iaateniz simuld-be ram? with flaw i 'mctims therein that the same may comfim'm to t'mz record an? the case in the 22. mm Qffigze.

Signed and sealed this 1% day 0f Mamh, A. L". 1929.

M. 31. Moan-2 (Seal) Acting flnmmissiomer m @mtants. 

